Ipsilateral ulcer and pre-ulcer detection method and apparatus

ABSTRACT

A system has a body with a base having a top surface with a receiving region to receive the bottom of a single foot. Among other things, the base may be in the form of an open or closed platform with a plurality of temperature sensors in communication with the top surface of the receiving region. The plurality of temperature sensors is within the receiving region and configured to activate after receipt of a stimulus applied to one or both the platform and the plurality of temperature sensors. A comparator is configured to form a temperature range as a function of the temperature value distribution and compare a percentage of the range size of the temperature distribution to a threshold value. An output produces ulcer information indicating the emergence of an ulcer or pre-ulcer when the percentage of the range size equals or exceeds the threshold value.

PRIORITY

This patent application is a continuation application of U.S. patentapplication Ser. No. 16/653,456, filed Oct. 15, 2019, and entitled,“IPSILATERAL ULCER AND PRE-ULCER DETECTION METHOD AND APPARATUS,” andnaming David R. Linders and Brian Petersen as inventors, the disclosureof which is incorporated herein, in its entirety, by reference, whichclaims priority from provisional U.S. patent application No. 62/752,589,filed Oct. 30, 2018, entitled, “IPSILATERAL ULCER AND PRE-ULCERDETECTION METHOD AND APPARATUS,” and naming David R. Linders and BrianPetersen as inventors, the disclosure of which is incorporated herein,in its entirety, by reference. The parent patent application (U.S. Ser.No. 16/653,456) also claims priority from provisional U.S. patentapplication No. 62/745,925, filed Oct. 15, 2018, entitled, “IPSILATERALULCER AND PRE-ULCER DETECTION METHOD AND APPARATUS,” and naming David R.Linders and Brian Petersen as inventors, the disclosure of which isincorporated herein, other than “Commented” indicia at line 25 of page22, in its entirety, by reference.

RELATED APPLICATIONS

This patent application is related to the following utility patent andits family members, the disclosure of which is incorporated herein, inits entirety, by reference:

-   U.S. Pat. No. 9,271,672, issued on Mar. 1, 2016, entitled, “METHOD    AND APPARATUS FOR INDICATING EMERGENCE OF AN ULCER,” and naming    David Robert Linders, Jonathan David Bloom, Jeffrey Mark Engler,    Brian Jude Petersen, Adam Geboff, and David Charles Kale, and as    inventors.

FIELD OF THE INVENTION

Various embodiments of the invention generally relate to ulcers onliving beings and, more particularly, various embodiments of theinvention relate to systems for evaluating portions of living beings forulcers.

BACKGROUND OF THE INVENTION

Open sores on an external surface of the body often form septic breedinggrounds for infection, which can lead to serious health complications.For example, foot ulcers on a diabetic's foot can lead to gangrene, legamputation, or, in extreme cases, death. The healthcare establishmenttherefore recommends monitoring a diabetic foot on a regular basis toavoid these and other dangerous consequences. Unfortunately, knowntechniques and systems for monitoring foot ulcers, among other types ofulcers, often are inconvenient to use, unreliable, or inaccurate, thusreducing compliance by the very patient populations that need it themost. It can be particularly difficult to use known techniques andsystems to accurately monitor and locate ulcers and pre-ulcers onamputees and others with only one foot.

SUMMARY OF VARIOUS EMBODIMENTS

In accordance with one embodiment of the invention, a foot ulcerdetection system has a body with a base having a top surface. The topsurface of the base has a receiving region configured to receive thebottom of a single foot. Among other things, the base may be in the formof an open platform or a closed platform. The system also has a set ofone or more temperature sensors in communication with the top surface ofthe receiving region of the platform. Specifically, the set oftemperature sensors are spaced apart within the receiving region andconfigured to activate after receipt of a stimulus (e.g., receipt of afoot or a power signal energizing the sensors) applied to one or boththe platform and the set of temperature sensors. The set of temperaturesensors are configured to communicate with the bottom of the foot in thereceiving region to ascertain a current temperature at each of a set ofdifferent spaced apart locations of the bottom of the foot. Accordingly,the set of temperature sensors are configured to produce a set oftemperature values and thus, each location has one associatedtemperature value.

The system also has a comparator operatively coupled with the set oftemperature sensors. The comparator is configured to determine adistribution of temperature values using the set of temperature values.The distribution has an interpercentile range between or including thezero percentile and the one hundred percentile of the set of temperaturevalues (i.e., some or all of those temperature values, or one or moreother temperature values within some range between the endpoints of theset of temperature values—those temperature values in theinterpercentile may include number(s) not in the set of temperaturevalues). The comparator further is configured to compare theinterpercentile range to a threshold value. The system further has anoutput, operatively coupled with the comparator, that is configured toproduce ulcer information relating to the emergence of an ulcer orpre-ulcer when the interpercentile range equals or exceeds the thresholdvalue.

The output may be coupled with the body, or may be remote from the body(e.g., at a remote site across a network). Ulcer information may includedata requiring further processing to indicate the emergence of an ulceror pre-ulcer, or it may have information ready to present to a user inan understandable format. In a corresponding manner, the output andcomparator may be spaced from and remote from the body.

In some embodiments, the set of temperature values includes a maximumtemperature value and a minimum temperature value. In that case, theinterpercentile range has the minimum temperature value at the zeropercentile and the maximum temperature value at the one hundredthpercentile. The interpercentile range may be between the zero percentileand the one hundredth percentile, or between one or two otherpercentiles. For example, the interpercentile range size may have alowest temperature value greater than the zero percentile or a highesttemperature value less than the one hundredth percentile. Moreover, theinterpercentile range may have less than all of the temperature valuesin the set of temperature values (e.g., where the endpoints of theinterpercentile range are not the minimum or maximum temperature valuesin the set of temperature values, or where only one of the notedendpoints is a minimum or maximum temperature value in the set oftemperature values).

The threshold may be between approximately 1 degree C. and approximately4 degrees C. (e.g., between approximately 1.4 degrees C. andapproximately 2.8 degrees C.). Those skilled in the art may set thedifferent locations to meet the application. For example, the set ofdifferent locations may be between four and one hundred locations (e.g.,4-6 locations) that relate to corresponding locations on the bottom ofthe foot.

Additional comparisons may further optimize the ability of the system todetect ulcers and pre-ulcers. For example, the system also may have asecond comparator operably coupled with the output. The secondcomparator is configured to determine a tendency statistic (i.e., one ofmean, median, and mode) from the set of temperature values. In addition,the second comparator also may be configured to produce a given value asa function of the tendency statistic and ambient temperature, and thencompare the given value to a second threshold value. In this example,the output is configured to produce the ulcer information also as afunction of the comparison of the given value to the second thresholdvalue. Among other things, the comparator may be configured to producethe given value by determining the difference between the tendencystatistic and the ambient temperature. The comparator may also beconfigured to produce the given value by determining the differencebetween the tendency statistic and some range value.

The comparator also may be configured to compare two of the sets of thetemperature values to produce a comparison value, and then determine thedifference between at least the comparison value and a third thresholdvalue. In this case, the output is configured to produce the ulcerinformation as a function of the difference between the comparison valueand the third threshold value.

In accordance with another embodiment, a method of detecting emergenceof a foot ulcer or a foot pre-ulcer, communicates the bottom of a singlefoot with a modality (e.g., a closed platform, open platform, or athermal camera). The closed or open platform includes a body having abase with a top surface having a receiving region configured to receivethe bottom of a single foot. The receiving region has a set oftemperature sensors in communication with (e.g., thermal or visualcommunication) the top surface of the receiving region, and the set oftemperature sensors are spaced apart within the receiving region.

In a manner similar to other embodiments, the method activates thetemperature sensors of the closed or open platform, and ascertains acurrent temperature at each of a set of different locations of thebottom of the foot after the foot is positioned in the receiving regionof the base and in contact with the top surface of the base.Accordingly, this act produces a set of temperature values with eachlocation having one associated temperature value. The method thenproduces a distribution of temperature values using the set oftemperature values. The distribution has an interpercentile rangecomprising at least two of the set of temperature values. Next, themethod compares the interpercentile range of temperatures to a thresholdvalue, and produces electronic output information having informationrelating to the emergence of an ulcer or pre-ulcer when theinterpercentile range size equals or exceeds the threshold value.

Illustrative embodiments of the invention are implemented as a computerprogram product having a computer usable medium with computer readableprogram code thereon. The computer readable code may be read andutilized by a computer system in accordance with conventional processes.

BRIEF DESCRIPTION OF THE DRAWINGS

Those skilled in the art should more fully appreciate advantages ofvarious embodiments of the invention from the following “Description ofIllustrative Embodiments,” discussed with reference to the drawingssummarized immediately below.

FIG. 1 schematically shows a foot having a prominent foot ulcer and apre-ulcer.

FIG. 2A schematically shows one use and form factor that may beimplemented in accordance with illustrative embodiments of theinvention.

FIG. 2B schematically shows an open platform that may be configured inaccordance with illustrative embodiments of the invention. This figurealso shows use by an amputee with a single foot.

FIG. 3A schematically shows an exploded view of one type of openplatform that may be configured in accordance with illustrativeembodiments of the invention.

FIG. 3B schematically shows a close-up view of the platform with detailsof the pads and temperature sensors in the foot receiving region.

FIG. 4 schematically shows a network implementing illustrativeembodiments of the invention.

FIG. 5 schematically shows an overview of various components ofillustrative embodiments of the invention.

FIG. 6 schematically shows details of a data processing module inaccordance with illustrative embodiments of the invention.

FIG. 7 schematically shows a comparator configured in accordance withillustrative embodiments of the invention.

FIG. 8 shows a process of identifying potential ulcers and pre-ulcersfor a single foot only in accordance with illustrative embodiments ofthe invention.

FIG. 9 schematically shows the bottom of a single foot and regions ofthat foot to receive temperature information in accordance withillustrative embodiments of the invention.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In illustrative embodiments, despite having less data than systemsrelying on two patient feet, a system effectively determines theexistence of ulcers and pre-ulcers of patients with a single foot (e.g.,amputees or patients with access to a single foot only, such as patientswith a full foot and another partial foot). To that end, an ulcerdetection system determines a interpercentile temperature range as afunction of a distribution of temperature values across prescribed partsof a single foot, and then compares that range size to a thresholdvalue. Next, the system produces output information indicating theemergence of an ulcer or pre-ulcer when the interpercentile temperaturerange size equals or exceeds the threshold value. Details ofillustrative embodiments are discussed below.

As known by those in the art, routine foot temperature monitoring hasbeen shown to be effective for identifying inflammation preceding footulcers or other inflammatory foot conditions. A traditional approachuses differences in temperatures between the right and left feet tocharacterize inflammation, and thus risk. Comparison of contralateraltemperature differences is known as asymmetry analysis.

Some of the patients at elevated risk to develop inflammatory footcomplications, however, have history of major lower extremityamputation, such as trans-femoral, trans-tibial, or ankledisarticulation. These patients thus suffer from a significant problemthat the prior art cannot solve—they cannot rely on the traditionalapproaches for foot temperature monitoring to identify inflammationbecause they lack the required anatomy and only have one foot. Usingspecific platforms and/or techniques, illustrative embodiments aim tosolve these problems by analyzing the temperatures of a single foot todetermine various pathologies related to inflammation in the foot, suchas diabetic foot ulcers, Charcot syndrome, claudication, and embolism.

Additionally, as discussed below, some patients may have only one footavailable for foot temperature monitoring due to ongoing treatment of awound to one foot or some other reason. As is well known by thoseskilled in the art, such treatment may require bandaging, casting, oruse of a boot. These patients also are unable to rely on traditionalapproaches for foot temperature monitoring using prior art techniquesknown to the inventors.

Specifically, illustrative embodiments analyze a patient's foot todetermine the risk of an ulcer emerging on its underside (i.e., on itssole). This permits patients, their healthcare providers, and/or theircaregivers to intervene earlier, reducing the risk of more seriouscomplications. To that end, a temperature detection modality (e.g., anopen or closed platform) receives the patient's foot and generatestemperature data that is processed to determine whether an ulcer orpre-ulcer will/has emerged, and/or the progression of a known ulcer orpre-ulcer. The modality may use any of a variety of different processes,discussed in detail below, such as comparing one or more portions of thefoot, or an interpercentile range of temperatures, to some prescribedother value, such as the environmental/ambient temperature, a prescribedthreshold, or the temperature of another portion of the foot.

Using that comparison, if the modality and/or its associated apparatusdetermines that the foot presents at least one of a number of prescribedpatterns and/or meets certain thresholds/requirements, then variousembodiments produce output information indicating whether an ulcer orpre-ulcer will/has emerged, and/or the progression of a known ulcer orpre-ulcer.

To analyze one foot, illustrative embodiments may use modalities andtechniques similar to those discussed in U.S. Pat. No. 9,271,672. Forexample, FIG. 1 schematically shows a bottom view of a patient's foot 10that, undesirably, has an ulcer 12 and a pre-ulcer 14 (described belowand shown in phantom since pre-ulcers 14 do not break through the skin).As one would expect, an ulcer 12 on this part of the foot 10 typicallyis referred to as a “foot ulcer 12.” Generally speaking, an ulcer is anopen sore on a surface of the body generally caused by a breakdown inthe skin or mucous membrane. Diabetics often develop foot ulcers 12 onthe soles of their feet 10 as part of their disease. In this setting,foot ulcers 12 often begin as a localized inflammation that may progressto skin breakdown and infection.

It should be noted that discussion of diabetes and diabetics is but oneexample and used here simply for illustrative purposes only.Accordingly, various embodiments apply to other types of diseases (e.g.,stroke, deconditioning, sepsis, friction, coma, etc.) and other types ofulcers—such embodiments may apply generally where there is a compressionor friction on the living being's body over an extended period of time.For example, various embodiments also apply to ulcers formed ondifferent parts of the body, such as on the back (e.g., bedsores),inside of prosthetic sockets, or on the buttocks (e.g., a patient in awheelchair). Moreover, some embodiments apply to other types of livingbeings beyond human beings, such as other mammals (e.g., horses ordogs). Accordingly, discussion of diabetic human patients having footulcers 12 is for simplicity only and not intended to limit allembodiments of the invention.

Many prior art ulcer detection technologies known to the inventorssuffered from one significant problem—patient compliance. If a diseasedor susceptible patient does not regularly check his/her feet 10, thenthat person may not learn of an ulcer 12 or a pre-ulcer 14 until it hasemerged through the skin and/or requires significant medical treatment.Accordingly, illustrative embodiments implement an ulcer monitoringsystem in any of a variety of forms—preferably in an easy to use formfactor or modality that facilitates and encourages regular use. One suchmodality/form factor involves a platform having a base and receivingregion for receiving the foot (both discussed in greater detail below).

FIGS. 2A and 2B schematically show one form factor, in which apatient/user steps on an open platform 16 that gathers data about thatuser's foot (or feet 10). As shown in FIG. 2A, the patient has only onenatural foot with which to gather data for making an assessment. Theother foot, in this embodiment, is a prosthetic. Other embodiments mayoperate without a prosthetic foot, or even with only a single foot thatitself has amputations (e.g., a single foot with only three toes).

In this example, the open platform 16 is in the form of a baseimplemented as a floor mat placed in a location where he the patientregularly stands, such as in front of a bathroom sink, next to a bed, infront of a shower, on a footrest, or integrated into a mattress. As anopen platform 16, the patient simply may step on the top sensing surface13 of the platform 16 (e.g., using a prosthetic where the other footwould have been, or supported by some object) to initiate the process.Accordingly, this and other form factors often do not require that thepatient affirmatively decide to interact with the platform 16. Instead,many expected form factors are configured to be used in areas where thepatient frequently stands during the course of their day without a footcovering. Alternatively, the open platform 16 may be moved to directlycontact the feet 10 of a patient that cannot stand. For example, if thepatient is bedridden, then the platform 16 may be brought into contactwith the patient's feet 10 while in bed. In this example, the patient'sfoot may be placed into a receiving region of the platform 16 to beginfoot analysis.

A bathroom mat or rug are but two of a wide variety of differentpotential form factors. Others may include a platform 16 resembling ascale, a stand, a footrest, a console, a tile built into the floor, or amore portable mechanism that receives at least one of the feet 10. Theimplementation shown in FIGS. 2A and 2B has a top surface area that islarger than the surface area of the foot 10 of the patient. In preferredembodiments, the receiving region is large enough to receive the foot10. This enables a caregiver to obtain a complete view of the patient'sentire sole, providing a more complete view of the foot 10.

The open platform 16 of various embodiments also has some indicia ordisplay 18 on its top surface 13 that can have any of a number offunctions. For example, the indicia/display 18 can turn a differentcolor or sound an alarm after the readings are complete, show theprogression of the process, or display results of the process. Ofcourse, the indicia or display 18 can be at any location other than onthe top surface 13 of the open platform 16, such as on the side, or aseparate component that communicates with the open platform 16. In fact,in addition to, or instead of, using visual or audible indicia, theplatform 16 may have other types of indicia, such as tactileindicia/feedback, our thermal indicia.

Rather than using an open platform 16, alternative embodiments may beimplemented as a closed platform 16, such as a shoe, shoe insert,insole, slipper or sock that can be regularly worn by a patient, or wornon an as-needed basis. For example, the insole of the patient's shoe orboot may have the functionality for detecting the emergence of apre-ulcer 14 or ulcer 12, and/or monitoring a pre-ulcer 14 or ulcer 12.Positioning the foot appropriately in such a platform to the receivingregion thus should be easier since the closed platform 16 may includefeatures that guide the foot to the appropriate location (e.g., thenatural outside of the platform 16, specialized extra elements, or otherapparatus). To monitor the health of the patient's foot (discussed ingreater detail below), the platform 16 of FIGS. 2A and 2B gatherstemperature data about a plurality of different locations on the sole ofthe foot 10. This temperature data provides the core informationultimately used to determine the health of the foot FIG. 3 schematicallyshows an exploded view of the open platform 16 configured and arrangedin accordance with one embodiment of the invention. Of course, thisembodiment is but one of a number of potential implementation and, likeother features, is discussed by example only.

As shown, the platform 16 is formed as a stack of functional layerssandwiched between a cover 20 and a rigid base 22. For safety purposes,the base 22 preferably has rubberized or has other non-skid features onits bottom side. FIG. 3A shows one embodiment of this non-skid featureas a non-skid base 24. The platform 16 preferably has relatively thinprofile to avoid tripping the patient and making it easy to use.

To measure foot temperature, the platform 16 has a receiving region 17on the top platform surface for receiving the foot 10. This receivingregion 17 is specially configured to communicate with the underside ofthe foot 10. In this embodiment, the receiving region 17 has an array,matrix, or other prescribed arrangement of temperature sensors 26 fixedin place directly underneath the cover 20. More specifically, thetemperature sensors 26 are positioned on a relatively large printedcircuit board 28. The sensors 26 preferably are laid out in atwo-dimensional array/matrix of stationary contact sensors on theprinted circuit board 28. In some embodiments, the pitch or distancebetween the preferably may be relatively small, thus permitting moretemperature sensors 26 on the array. Among other things, the temperaturesensors 26 may include temperature sensitive resistors (e.g., printed ordiscrete components mounted onto the circuit board 28), graphenetemperature sensors, thermocouples, fiberoptic temperature sensors, or athermochromic film. Accordingly, when used with temperature sensors 26that require direct contact, illustrative embodiments form the cover 20with a thin material having a relatively high thermal conductivity. Theplatform 16 also may use temperature sensors 26 that can still detecttemperature through a patient's socks.

Other embodiments may use noncontact temperature sensors 26, such asinfrared detectors. Indeed, in that case, the cover 20 may have openingsto provide a line of sight from the sensors 26 to the sole of the foot10. Accordingly, discussion of contact sensors is by example only andnot intended to limit various embodiments. As discussed in greaterdetail below and noted above, regardless of their specific type, theplurality of sensors 26 generate a plurality of correspondingtemperature data values for a plurality of portions/spots on thepatient's foot 10 to monitor the health of the foot 10.

Some embodiments, however, may have a smaller number of temperaturesensors 26 that are spaced apart (e.g., the distance between the sensors26 is many times the largest dimension of the sensors 26 themselves,such as ten times or more). For example, as discussed below, someembodiments of the receiving region 17 may have as few as four or sixsensors 26 spaced apart at prescribed portions of the platform (e.g.,see FIG. 9 , discussed below). Use of fewer temperature sensors 26 maybe assisted by indicia or other means for directing a patient on theappropriate location for their foot to contact the top surface 13 of thecover 20—to align the foot with the appropriate sensors 26. Illustrativeembodiments with a larger array of temperature sensors 26, however, maynot require such assistance. Instead, such latter embodiments maydetermine the orientation and location of specific sensors to determinethe desired smaller number of temperature values required (see belowprocesses for further information on this process).

Some embodiments thus also may use pressure sensors for variousfunctions, such as to determine the orientation of the feet 10 and/or toautomatically begin the measurement process. Among other things, thepressure sensors may include piezoelectric, resistive, capacitive, orfiber-optic pressure sensors. This layer of the platform 16 also mayhave additional sensor modalities beyond temperature sensors 26 andpressure sensors, such as positioning sensors, GPS sensors,accelerometers, gyroscopes, and others known by those skilled in theart.

Accordingly, illustrative embodiments for performing thermal analysis ofa foot may obtain temperature input from a variety of sensor types,including thermal cameras, open platforms with contact or non-contacttemperature sensors, socks, shoes, insoles, bandages, wraps, individualpoint temperature measurements by hand. Temperature sensors may includeinfrared photodiodes, phototransistors, resistive temperature detectors,thermistors, thermocouples, fiberoptic, thermochromic sensors. Thoseskilled in the art should understand that these temperature sensingmodalities and sensor types are examples of options available for use,and that some or all of the analysis methods described below are notdependent on the sensor modality employed in the system.

To reduce the time required to sense the temperature at specific points,illustrative embodiments position an array of heat conducting pads 30over the array of temperature sensors 26. To illustrate this, FIG. 3Bschematically shows a small portion of the array of temperature sensors26 showing four temperature sensors 26 and their pads 30. Thetemperature sensors 26 are drawn in phantom because they preferably arecovered by the pads 30. Some embodiments do not cover the sensors 26,however, and simply thermally connect the sensors 26 with the pads 26.

Accordingly, each temperature sensor 26 in this embodiment has anassociated heat conducting pad 30 that channels heat from onetwo-dimensional portion of the foot 10 (considered a two dimensionalarea although the foot may have some depth dimensionality) directly toits exposed surface 13. The array of conducting pads 30 preferably takesup the substantial majority of the total surface area of the printedcircuit board 28. The distance between the pads 30 thermally isolatesthem from one another, thus eliminating thermal short-circuits.

For example, each pad 30 may have a square shape with each side having alength of between about 0.1 and 1.0 inches. In the larger sensor arrays,the pitch between pads 30 thus is less than that amount. Accordingly, asa further detailed example, some embodiments may space the temperaturesensors 26 about 0.4 inches apart with 0.25 inch (per side) square pads30 oriented so that each sensor 26 is at the center of the square pads30. This leaves an open region (i.e., a pitch) of about 0.15 inchesbetween the square pads 30. Among other things, the pads 30 may beformed from a film of thermally conductive metal, such as a copper. Someembodiments that use fewer sensors 26, such as those that use sixsensors to align with prescribed portions of the foot (e.g., see FIG. 9, discussed below), may space the pads farther apart to gather dataabout one specific sector/portion of the foot 10.

As suggested above, some embodiments do not use an array of temperaturesensors 26. Instead, such embodiments may use a single temperaturesensor 26 that can obtain a temperature reading of most or all of thesole. For example, a single sheet of a heat reactive material, such as athermochromic film (noted above), or similar apparatus should suffice.As known by those in the art, a thermochromic film, based on liquidcrystal technology, has internal liquid crystals that reorient toproduce an apparent change in color in response to a temperature change,typically above the ambient temperature. Alternatively, one or moreindividual temperature sensors 26, such as thermocouples or temperaturesensor resistors, may be movable to take repeated temperature readingsacross the bottom of the foot 10. Other embodiments may have a pluralityof temperature sensors 26 that provide enough data to form a thermogram.In a manner to the thermochromic film example, specific locations ofinterest may be used to perform various comparisons and analyses. Athermal camera also may be integrated into one of the noted modalities,used in conjunction with another of those modalities (e.g., an open orclosed platform in that case may not use temperature sensors 26 in thatcase), or used with the relevant system components in place of one ofthe noted modalities.

In various other embodiments, the base 22 of the platform/modality mayinclude other similar structure that supports various other components,such as, in some cases, temperature sensors 26. For example, a closedplatform 16 implemented as a shoe, the base 22 may include the insole.

To operate efficiently, the open platform 16 should be configured sothat its top surface 13 contacts substantially the entire sole of thepatient's foot 10. To that end, the platform 16 has a flexible andmovable layer of foam 32 or other material that at least generallyconforms to the user's foot 10. For example, this layer should conformto the arch of the foot 10. Of course, the sensors 26, printed circuitboard 28, and cover 20 also may be similarly flexible and yet robust toconform to the foot 10 in a corresponding manner. Accordingly, theprinted circuit board 28 preferably is formed largely from a flexiblematerial that supports the circuit. For example, the printed circuitboard 28 may be formed primarily from a flex circuit that supports thetemperature sensors 26, or it may be formed from strips of material thatindividually flex when receiving feet. Alternative embodiments may nothave such flexibility (e.g., formed from conventional printed circuitboard material, such as FR-4) and thus, produce less effective data.

The rigid base 22 positioned between the foam 32 and the non-skid base24 provides rigidity to the overall base structure. In addition, therigid base 22 is contoured to receive a motherboard 34, a battery pack36, a circuit housing 38, and additional circuit components that providefurther functionality. For example, the motherboard 34 may containintegrated circuits and microprocessors that control the functionalityof the platform 16.

In addition, the motherboard 34 also may have a user interface/indiciadisplay 18 as discussed above, and a communication interface to connectto a larger network 44, such as the Internet. The communicationinterface may connect wirelessly or through a wired connection with thelarger network 44, implementing any of a variety of different datacommunication protocols, such as Ethernet. Alternatively, thecommunication interface 40 can communicate through an embedded Bluetoothor other short range wireless radio that communicates with a cellulartelephone network 44 (e.g., a 3G or 4G network).

The platform 16 also may have edging 42 and other surface features thatimprove its aesthetic appearance and feel to the patient. The layers maybe secured together using one or more of an adhesive, snaps, nuts,bolts, or other fastening devices. The platform 16 may also be taperedat its edges to prevent the platform 16 from being a tripping hazard tothe user.

Although they gather temperature and other data about the patient'sfoot, illustrative embodiments may locate additional logic formonitoring foot health at another location. For example, such additionallogic may be on a remote computing device. To that and other ends, FIG.4 schematically shows one way in which the platform 16 can communicatewith a larger data network 44 in accordance with various embodiments theinvention. As shown, the platform 16 may connect with the Internetthrough a local router, through its local area network, or directlywithout an intervening device. This larger data network 44 (e.g., theInternet) can include any of a number of different endpoints that alsoare interconnected. For example, the platform 16 may communicate with ananalysis engine 46 that analyzes the thermal data from the platform 16and determines the health of the patient's foot 10. The platform 16 alsomay communicate directly with a healthcare provider 48, such as adoctor, nurse, relative, and/or organization charged with managing thepatient's care. In fact, the platform 16 also can communicate with thepatient, such as through text message, telephone call, e-mailcommunication, or other modalities as the system permits.

FIG. 5 schematically shows a block diagram of a foot monitoring system,showing the platform 16 and the network 44 with its interconnectedcomponents in more detail. As shown, the patient communicates with theplatform 16 by standing on or being received in some manner by thereceiving region 17 having the sensors 26, which is represented in thisfigure as a “sensor matrix 52” (although other embodiments of thesensors 26 are not arranged as a matrix). A data acquisition block 54,implemented by, for example, the motherboard 34 and circuitry shown inFIG. 3 , controls acquisition of the temperature and other data forstorage in a data storage device 56. Among other things, the datastorage device 56 can be a volatile or nonvolatile storage medium, suchas a hard drive, high-speed random-access-memory (“RAM”), or solid-statememory. The input/output interface port 58, also controlled by themotherboard 34 and other electronics on the platform 16, selectivelytransmits or forwards the acquired data from the storage device to theanalysis engine 46 on a remote computing device, such as a server 60.The data acquisition block 54 also may control the userindicators/displays 18, which provide feedback to the user through theabove mentioned indicia (e.g., audible, visual, or tactile).

The analysis engine 46, on the remote server 60, analyzes the datareceived from the platform 16 in conjunction with a health dataanalytics module 62. A server output interface 64 forwards the processedoutput information/data from the analysis engine 46 and health dataanalytics module 62 toward others across the network 44, such as to aprovider, a web display, or to the user via a phone, e-mail alert, textalert, or other similar way.

This output message may have the output information in its relativelyraw form for further processing. Alternatively, this output message mayhave the output information formatted in a high-level manner for easyreview by automated logic or a person viewing the data. Among otherthings, the output message may indicate the actual emergence of an ulcer12 or a pre-ulcer 14, the risk of the emergence of an ulcer 12 or apre-ulcer 14, or simply that the foot 10 is healthy and has no risks ofulcer 12 or pre-ulcer 14. In addition, this output message also may haveinformation that helps an end-user or healthcare provider 48 monitor anulcer 12 or pre-ulcer 14.

Using a distributed processing arrangement like that shown in FIG. 5 hasa number of benefits. Among other things, it permits the platform 16 tohave relatively simple and inexpensive components that are unobtrusiveto the patient. Moreover, this permits a “software-as-a-service”business model (“SAAS model”), which, among other things, permits moreflexibility in the functionality, typically easier patient monitoring,and more rapid functional updates. In addition, the SAAS modelfacilitates accumulation of patient data to improve analytic capability.

Some embodiments may distribute and physically position the functionalcomponents in a different manner. For example, the platform 16 may havethe analysis engine 46 on its local motherboard 34. In fact, someembodiments provide the functionality entirely on the platform 16 and/orwithin other components in the local vicinity of the platform 16. Forexample, all of those functional elements (e.g., the analysis engine 46and other functional elements) may be within the housing formed by thecover 20 and the rigid base 22. Accordingly, discussion of a distributedplatform 16 is but one of a number of embodiments that can be adaptedfor a specific application or use.

Those skilled in the art can perform the functions of the analysisengine 46 using any of a number of different hardware, software,firmware, or other non-known technologies. FIG. 6 shows severalfunctional blocks that, with other functional blocks, may be configuredto perform the functions of the analysis engine 46. This figure simplyshows the blocks and is illustrative of one way of implementing variousembodiments.

Among other things, the analysis engine 46 of FIG. 6 may have athermogram generator 66 configured to form a thermogram of the patient'sfoot or feet 10 (if a thermogram is to be used in the analysis) based ona plurality of temperature readings from the bottom of the foot 10, anda pattern recognition system 68 configured to determine whether thethermogram presents any of a number of different prescribed patterns.Pattern data and other information may be stored in a local memory 76.As discussed below, if the thermogram and/or the plurality oftemperature readings presents any of these prescribed patterns, then thefoot 10 may be unhealthy in some manner (e.g., having a pre-ulcer 14 oran ulcer 12).

The analysis engine 46 also has an analyzer 70 configured to produce theabove noted output information, which indicates any of a number ofdifferent conditions of the foot 10. For example, the output informationmay indicate the risk that an ulcer 12 will emerge, the emergence of apre-ulcer 14 (i.e., the first indication of a pre-ulcer 14), theprogression of a known ulcer 12, or the emergence of a new ulcer 12(i.e., the first indication of any given ulcer 12 to the patient andassociated support). Communicating through some interconnect mechanism,such as a bus 72 or network connection, these modules cooperate todetermine the status of the foot 10, which may be transmitted orforwarded through an input/output port 74 that communicates with theprior noted parties across the larger data network 44.

Indeed, it should be noted that FIGS. 5 and 6 only schematically showeach of the noted components and a single embodiment. Those skilled inthe art should understand that each of these components can beimplemented in a variety of conventional manners, such as by usinghardware, software, or a combination of hardware and software, acrossone or more other functional components. For example, the analyzer 70may be implemented using a plurality of microprocessors executingfirmware. As another example, the analyzer 70 may be implemented usingone or more application specific integrated circuits (i.e., “ASICs”) andrelated software, or a combination of ASICs, discrete electroniccomponents (e.g., transistors), and microprocessors. Accordingly, therepresentation of the analyzer 70 and other components in a single boxof FIG. 5 is for simplicity purposes only. In fact, in some embodiments,the analyzer 70 of FIG. 5 is distributed across a plurality of differentmachines—not necessarily within the same housing or chassis.

Illustrative embodiments use one or combinations of variousmethods/processes/techniques, along with prescribed physical modalities,to assess and make determinations about foot health using a single footonly. Specifically, illustrative embodiments may use one or combinationsof one or more methods/techniques to make ipsilateral temperaturecomparisons. To make those assessments and determinations, illustrativeembodiments use a comparator 80, such as that shown in FIG. 7 . Aspreviously noted, the comparator 80 can be used as part of the system ofFIG. 5 (e.g., part of the analysis engine 46 or other component of theanalysis engine 46), as a separate component local to or remote from theplatform 16, or as an adjunct with the system of FIG. 5 .

Each of these components is operatively connected by any conventionalinterconnect mechanism. FIG. 7 simply shows a bus 79 communicating eachthe components. Those skilled in the art should understand that thisgeneralized representation can be modified to include other conventionaldirect or indirect connections. Accordingly, discussion of a bus is notintended to limit various embodiments.

As with other systems discussed above, it should be noted that FIG. 7only schematically shows each of these components. Accordingly, in asimilar manner, those skilled in the art should understand that each ofthese components can be implemented in a variety of conventionalmanners, such as by using hardware, software, or a combination ofhardware and software, across one or more other functional components.For example, a distribution processor 86 may be implemented using aplurality of microprocessors executing firmware. As another example, thedistribution processor 86 may be implemented using one or moreapplication specific integrated circuits (i.e., “ASICs”) and relatedsoftware, or a combination of ASICs, discrete electronic components(e.g., transistors), and microprocessors. Accordingly, therepresentation of the distribution processor 86 and other components ina single box of FIG. 7 is for simplicity purposes only. In fact, in someembodiments, the distribution processor 86 is distributed across aplurality of different machines—not necessarily within the same housingor chassis.

It should be reiterated that the representation of FIG. 7 is asimplified representation of an actual comparator. Those skilled in theart should understand that such a device may have many other physicaland functional components, such as central processing units, other dataprocessing modules, and short-term memory. Accordingly, this discussionis in no way intended to suggest that FIG. 7 represents all of theelements of a comparator.

As with many devices, the comparator 80 has an input 82 for receivingdata and an output 84 for processing and/or forwarding processed data.The output 84 and other components may be part of the same physicaldevice (e.g., coupled with the platform 16 or base 22), or separate(e.g., components across the Internet or other network). The output datamay have additional functionality to, either alone or with othercomponents, produce ulcer information relating to the emergence of anulcer or pre-ulcer. The comparator 80 also has a distribution processor86 configured to determine the distribution of temperature valuesproduced by the temperature sensors 26, and a tendency processor 88 todetermine tendency data from the temperature values (e.g., the mean,median, and/or mode).

The comparator 80 also has a comparison processor 90 configured tocompare various values. Among other things, the comparison processor 90may effectively form one or more comparison processors 90 to comparevarious items, such as an interpercentile range to a threshold value, orto compare a tendency statistic to another threshold value. Indeed thecomparison processor 90 may have the functionality to make othercomparisons. Accordingly, as noted above, representation of thecomparison processor 90 as a single box in the figure is merelyschematic and not intended to imply a single comparison processor 90with a single function.

As noted above, in illustrative embodiments, the system determines aninterpercentile range of temperatures at prescribed portions of thesingle foot using a temperature distribution, and compares the thatrange with a prescribed threshold value. If size of the range is equalto or exceeds the threshold value, then the system may indicate that thesingle foot may require further assistance due to a potential ulcer orpre-ulcer. In fact, the results in some embodiments may also indicate apotentially ischemic condition with the single foot.

More specifically, as known by those in the art, a temperaturedistribution in this context includes a statistical function thatdescribes the possible temperatures values and likelihoods of thosevalues sampled on the foot. Instead or in addition, the temperaturedistribution also may comprise a finite set of specific temperaturevalues, including a set having the measured temperature values only, ora set having the measured temperature values and other temperaturevalues derived from the measured temperature values. Some of the data inthe distribution may be calculated and/or some of the data in thedistribution may be actual (e.g., actual temperature detected by atemperature sensor 26).

The data in a temperature distribution is considered to form a pluralityof percentiles. For example, if the distribution has 100 differenttemperature values, each temperature value would by definition be in adifferent percentile—from the zero percentile to the one hundredthpercentile (in this case, each would be a whole number percentile).Illustrative embodiments take advantage of a range of these percentiles,known as the “interpercentile range” (discussed above and below) todetermine foot health. In particular, the interpercentile range is thedifference of temperature values at two different percentiles in thedynamic range. For example, to calculate the interpercentile range, someembodiments may determine the difference between the end-pointpercentiles (e.g., the zero percentile and the one hundred percentilevalues), while others may determine the difference between temperaturevalues (either estimated/interpolated/calculated or actual) betweenother percentiles. Still other embodiments may use temperature values atone of the end-point percentiles and some other non-end-point percentile(e.g., between the zero percentile and the ninetieth percentile). Thoseskilled in the art can select the appropriate interpercentile range.

To those ends, FIG. 8 shows a process of identifying potential ulcersand pre-ulcers for a single foot only in accordance with illustrativeembodiments of the invention. It should be noted that this process (andothers discussed below) is substantially simplified from a longerprocess that normally would be used to identify potential ulcers andpre-ulcers. Accordingly, the process can have other steps that thoseskilled in the art likely would use. In addition, some of the steps maybe performed in a different order than that shown, or at the same time.Those skilled in the art therefore can modify the process asappropriate.

The process of FIG. 8 begins at step 800, in which the foot communicateswith the receiving region 17 of the platform 16. To that end, if usingthe modality shown in FIGS. 2A and 2B, the patient may step onto the topsurface 13 of the open platform 16. In illustrative embodiments thathave fewer but spaced apart temperature sensors 26, the single, naturalfoot 10 of the patient preferably stands on the receiving region 17 ofthe platform 16, such as the portion having the spaced apart temperaturesensors 26. In closed platform embodiments, the patient may insert theirfoot into a shoe, sock or similar device and contact the foot receivingregion 17 in that modality. The temperature sensors 26 may directly orindirectly conductively contact the foot, or may contact the foot inother ways, such as using optics to take non-contact temperaturemeasurements at the specific foot locations. The top surface 13 may beconsidered to act at least in part as the input 82 to the comparator 80of FIG. 7

FIG. 9 schematically shows the general positions of the temperaturesensors 26 relative to the bottom of the foot, when the foot 10 isproperly positioned in the receiving region 17, in illustrativeembodiments of the invention. Indeed, some embodiments may have sixsensors 26, while others may have more or fewer (e.g., four sensors, sixsensors, one hundred sensors, or a range between two of those numbers).The sensor locations in this figure are shown generically with an “X.”

Returning to FIG. 8 , the process continues to step 802, which activatesthe temperature sensors 26. Among other ways, the temperature sensors 26may be activated manually, automatically, or virtually before, during,or after the patient communicates their foot to the platform 16. Forexample, power may be applied to the temperature sensors 26 by manuallyselecting or switching a power switch to an on position, virtuallyswitching on the power via a software application, or automatically bylogic or contact sensor (not shown) on the platform 16 sensing the foot10 in the receiving region 17.

Next, the distribution processor 86 produces a distribution of thetemperatures detected by the temperature sensors 26 (804) and, usingthat distribution, forms the interpercentile range (step 806). To thatend, the distribution processor 86 may determine the percentiles of thedata from the temperature distribution, and then determine which twopercentiles to use to form the interpercentile range. That may be asimple process of simply taking the difference between the maximum andminimum temperature values (i.e., the end-points of the temperaturerange). Other embodiments, however, may be configured, either manuallyor automatically (e.g., using a database), to select some otherpercentile within the temperature range. For example, theinterpercentile range may use temperature values between the firstpercentile and the ninety-ninth percentile. As noted above, these valuesmay be actual values or calculated from the set of temperature valuesused to form the temperature distribution. Using one or morenon-end-point percentiles may advantageously reduce noise (e.g., thelowest temperature data point may have not adequately communicated withits temperature sensor 26 and therefore, appears much colder than itsactual temperature.

As noted above, however, the distribution may simply include actualtemperature values or a relatively small set of temperature values thatare both actual and calculated. Step 806 therefore may simply select anytwo of these values to effectively form the interpercentile rangewithout affirmatively calculating the percentiles.

At step 808, the distribution processor 86 compares the interpercentilerange temperature value (i.e., a temperature difference) against aprescribed or other threshold value (i.e., another temperature value).That threshold value should be carefully chosen and be consistent withthe percentiles selected and other known information (e.g., patientinformation, modality information, etc.). When using the end-points ofthe set of temperature values, for example, the inventors discoveredthat a threshold value from about 1 to about 4 degrees C. should providesatisfactory results. During testing, the inventors discovered that avalue between about 1.4 degrees C. and about 2.8 degrees C. producedeven better results.

In illustrative embodiments, if the interpercentile range size is equalto or exceeds the threshold value (or if it simply exceeds the thresholdvalue), then the patient's foot may have a health issue, such as anulcer or pre-ulcer. During testing, the inventors were surprised todiscover that this comparison produced accurate results a significantproportion of the time when using the discussed modalities (e.g., theplatforms 16 with the receiving region 17, sensors 26 that actuate asrequired, etc.). Among other reasons, results of this type can often bedominated by noise producing a high or low end of the range that is wellbeyond those of the actual end points without the noise. For example,the inventors were concerned that a toe may not sufficiently contact acontact temperature sensor 26, thus appearing cold and producing a muchlower low end of the range. They recognized, however, that with closedplatforms 16, as well as with open platforms 16, these noise basedextremes were less of an issue than originally expected. The platform 16and its receiving region 17 therefore may obviate these issues.

In fact, the inventors unexpectedly recognized that this comparison alsocan signal an ischemic condition in the foot 10 that requires treatment.Accordingly, this process may alert a patient and/or caregiver to twopotentially common dangerous and life threatening conditions fordiabetics—foot ischemia and foot ulcers/pre-ulcers. Accordingly, therange of a set of foot temperature data captures both abnormally warmlocations and abnormally cool locations and conveniently presents it asa single statistic that can be easily compared to a threshold.

Alternatively, some embodiments may measure the temperature of acontinuous region on the foot. If necessary, this embodiment may excludethe data within a margin from the edges of the foot. After measuringthat temperature, this embodiment calculates the range of temperatureswithin the region and compares the range to a predetermined threshold todetermine if the temperature pattern is indicative of some pathology.This alternative embodiments also effectively performs steps 804-808.

The process continues to step 810, which considers whether the footrequires further processing to provide even more accurate results. Thismay be required in certain applications, or be unnecessary. Someembodiments have a selectable user interface to augment steps 800-808with one of the below listed processes. Specifically, the method mayexecute further processes that include one or more of the following(step 812):

Process 1: Simple Comparison Between Locations

In the absence of a contralateral foot for comparison, the temperaturesat any two locations on the foot 10 may be compared. For example, theheel may serve as a stable reference point due to its relativetemperature stability over time compared to more distal portions of thefoot 10.

-   -   Variant A: Absolute value above certain threshold.    -   Measure the temperature at two locations, calculate the absolute        value of the difference between the two locations, and compare        the difference to a predetermined threshold (e.g., two degrees        C.) to determine if the temperature pattern is indicative of        some pathology.    -   Variant B: Asymmetric threshold.    -   Measure the temperature at two locations on the foot 10.        Subtract the temperature a Location 1 from a Location 2 and        compare the difference to a Threshold A. Then subtract Location        2 from Location 1 and compare it to Threshold B, where Threshold        A is different from Threshold B. Then determine if either of the        differences exceed the two different predetermined thresholds.        This variant has the advantage of enabling detection of        pathologies that result in an abnormally warm region as well as        pathologies that may result in an abnormally cool region where        the definition of abnormal is dependent on whether the region is        warmer or cooler than another region.    -   Variant C: Unique thresholds for different locations.    -   Measure the temperature at three locations on the foot 10.        Subtract Location 1 from Location 2 and compare it to        Threshold A. Then subtract Location 3 from Location 2 and        compare it to Threshold B. Then determine if either of the        differences exceed the two different predetermined thresholds.        This variant enables optimizing accuracy for various anatomical        locations. For example, the toes may require a higher threshold        than the heel because of the greater temperature variation at        more distal regions of the foot 10.

Process 2: Comparison of Locations to a Statistic

Individual locations may be compared to a statistic that summarizes thetemperatures over the whole foot 10 instead of relying on a singlelocation for comparison, which may present with unstable temperaturepatterns over time.

-   -   Variant A: Comparison to a central tendency statistic (such as        the mean or median).    -   Measure the temperature over a plurality of discrete locations        or over a continuous portion of the foot 10 and use the tendency        processor 88 to calculate the mean or median temperature.        Measure the temperature of another location either within the        region of the average or outside of it. Then subtract the        average from the temperature in the location of interest and        compare it to a threshold.    -   Variant B: Comparison to the minimum.    -   Calculate the minimum temperature among a set of discrete        temperature values or from within a continuous portion of the        foot 10. If using a continuous portion of the foot 10, the        region may exclude the data within a certain margin from the        edges of the foot 10. Measure the temperature of another        location either within the region of the average or outside of        it. Then subtract the minimum from the temperature in the        location of interest and compare it to a threshold.    -   Variant C: Comparison to a percentile.    -   Similar to Variant B, except instead of calculating the minimum        temperature value for comparison, calculate a predetermined        percentile, such as the 10th percentile. This approach avoids        extremes in the distribution of temperature at the low or the        high side, which may result in inaccurate analyses.    -   Variant D: Comparison with a statistical distribution.    -   Compute a statistical distribution of the temperatures among a        set of discrete temperature values or from within a continuous        portion of the foot 10. Measure the temperature of another        location either within the region of the average or outside of        it. Then determine if the location of interest is within the        distribution using common statistical methods.

Process 3: Change Over Time

In some pathologies, the absolute temperature at a given time is not asinformative as the change in temperatures over time. Chronic conditionsmay present as slow changes over a long time and acute conditions maypresent as fast onset or short-lived patterns.

-   -   Variant A: Simple threshold above a baseline.    -   Illustrative embodiments measure and store the foot temperature        at a baseline time reference. Then for a later time t, this        embodiment measures the foot temperature again and compares the        temperatures at time t with the temperatures at baseline and        determines if any location has changed in temperature from the        baseline more than a predetermined threshold. Alternatively,        this embodiment may measure the difference in temperatures        between locations on the foot 10 and compare the spatial        differences with the baseline spatial differences. This method        has the advantage of personalizing the analysis to an        individual's idiosyncratic foot temperature patterns. However,        it assumes that the baseline temperatures are a healthy        reference location, which may not be true for individuals        healing from a recent wound or with other active pathology.    -   Variant B: Moving average baseline.    -   In a related embodiment, the baseline temperatures may be        calculated as a moving average or a filtered resultant from a        time series of multiple sets of temperature data from various        locations in time. The average may be taken from a small number        of samples to optimize for detecting acute changes in foot        temperatures or from a large number of samples to optimize for        detecting subtle changes or chronic conditions.    -   Variant C: Integral of temperature change over time.    -   In yet another embodiment, the foot temperatures may be compared        to a baseline reference or a static threshold for each set of        data values in a time series of samples. These comparisons may        then be summed, integrated, or otherwise aggregated to generate        a summary statistic for the change over time. This approach has        an advantage of emphasizing persistent changes over time while        filtering out noisy or inconsistent temperature fluctuations.    -   Variant D: Change in temperature as a response to a stimulus.    -   In yet another embodiment, the foot's response to a stimulus may        be monitored over time. For example, when a foot is placed on a        cold or room temperature platform, its response to that exposure        over several seconds to several minutes may indicate the        vascular health of the foot and the ability of the blood vessels        to supply fresh blood to warm the foot. In another example, a        foot's thermal response to exercise or other physical activity        such as walking may indicate its neurological or vascular        health. For example, a foot that becomes abnormally warm during        physical activity may lack the physiological mechanisms to        thermoregulate.

Process 4: Comparison with Ambient

Comparing foot temperature with ambient temperature provides anopportunity to detect inflammation in the foot 10 in cases where theremay be no spatial variation within the foot 10 although the entire foot10 is inflamed and at elevated temperature.

-   -   Variant A: Compare a central tendency statistic to ambient. This        embodiment measure the ambient temperature using either        background signal from the temperature sensor 26 (e.g., the        background of a thermal camera image or non-foot region from a        2D temperature scan) or from a separate temperature sensor 26        that is not measuring foot temperature. This embodiment also        measures the temperature across the foot 10 and calculates a        central tendency statistic (e.g., mean, median, mode). Next,        this embodiment compares the central tendency statistic to the        ambient temperature and determines if the difference exceeds a        predetermined threshold.    -   Variant B: Compare a specific location to ambient.    -   A related embodiment measures ambient temperature, and then        measures the foot temperature at a specific location or region        on the foot 10. It then compares the temperature at that        location to ambient temperature and determines if the difference        exceeds a predetermined threshold. This variant has a benefit of        allowing the clinician or researcher to select a consistent        location on the foot 10 with relatively stable temperatures that        is not as susceptible to environmental or other temporary        perturbations as other locations.    -   Variant C: Compare the maximum to ambient.    -   Another related embodiment measures ambient temperature, and        then measures the foot temperatures over the whole foot 10 and        calculates the maximum temperature of the foot 10. It then        compares the maximum to ambient temperature and determines if        the difference exceeds a predetermined threshold. This variant        is expected to provide good sensitivity in cases where the        warmest portion of the foot 10 may move from scan to scan.

Process 5: Comparison with Body Temperature

This method is similar to Process 4, but less susceptible tointermittent or irregular fluctuations in ambient temperature due tochanging environmental conditions. Comparing foot temperature with bodytemperature may provide a more accurate basis for detecting pathology byaccounting for external variables that affect foot temperature.

-   -   Variant A: Comparing to internal body temperature.    -   This embodiment measures internal body temperature either at the        core or preferably at the limb closest to the surface        measurement location. It then compares the surface foot        temperature measurements to the internal body temperature and        determine if the difference exceeds a predetermined threshold.    -   Variant B: limb surface temperature.    -   This embodiment measures the surface temperature of the limb        preferably close to the foot measurement location (e.g., ankle        or leg). It then compares the surface foot temperature        measurements to the surface limb temperature and determines if        the difference exceeds a predetermined threshold. This variant        is easier to acquire than internal body temperature as surface        temperature sensors 26 may be adhered to the skin to collect        surface temperature. This approach has the added benefit of        limiting the effects of ambient temperature, physical activity,        and vascularity, which would affect the limb as well as the foot        10.

Process 6: Isothermal Area

The size of a region of elevated temperature may be more informativethan the specific temperature of that region for certain pathologies,such as monitoring wound healing.

-   -   Variant A: Comparing an isothermal area.    -   This embodiment chooses a comparison from any of the processes        described above and calculates the difference between each        location in the foot temperature data set and the comparison        value. It then determines which locations, pixels, or regions        are above a predetermined threshold. Next, it calculates the        area of the region that exceeds that threshold in number of        points, pixels, or area (e.g., cm2). It determines if the area        of elevated temperature exceeds a predetermined threshold.    -   Variant B: Monitoring isothermal area over time.    -   This is similar to Method 6, Variant A except that the        determination is made as to whether the isothermal area has        changed in size over time.

Returning to step 810, if no further processing is necessary, or aftercompleting step 812, the process concludes at step 814, which produceselectronic output information, using the output 84, having data relatingto the analysis. As discussed above with regard to FIG. 5 , this datamay be in a form that is readily human understandable and/or storable,or may be in a format that needs further processing. This outputinformation thus may include ulcer information relating to the emergenceof an ulcer or pre-ulcer when the percentage of the range size equals orexceeds the threshold value. For example, the output information mayhave information indicating the presence of a pre-ulcer and the dataaround the steps performed and the temperature values, ranges, and/ordifferences, depending on the steps performed. This output informationalso may have information relating to an ischemic foot condition. Theoutput information alternatively may have information indicating thatthe foot 10 is healthy and has no maladies (e.g., if the percentage ofthe range size is less than the threshold value. Indeed, the outputinformation also may have information relating to one or more of theadditional processes noted above.

One skilled in the art should recognize that the results may have anaccuracy that may be higher or lower depending on the configuration ofthe system. Thus, although the system may be 90 percent accurate, forexample, it is not perfect and may have some false positives and falsenegatives. The platform 16, base, receiving region 17, sensors 26, etc.can be configured to optimize performance.

By themselves, some of the above noted process options and theirvariants (including the process of FIG. 8 ) may detect one distinct typeof pathology in the foot 10 and can be optimized to detect thatpathology with a high degree of sensitivity and specificity. However,just using one method may not generalize to other types of pathologies.For example, comparing the temperature of the hallux with the heel isbeneficial to determine if the hallux may have localized inflammation.However, if the whole foot 10 is inflamed, the temperature differencebetween those locations will not be significant and may therefore notdetect the systemic inflammation. The inventors discovered thatcombining this with another method, such as comparing the heeltemperature with ambient temperature to detect systemic inflammation,may improve the probability of detecting either pathological condition.

Accordingly, although some provide beneficial results alone,illustrative embodiments may combine two or more of noted processesand/or their variants. For example, two or more of those methods may becombined with simple logical terms or in linear combinations to providea more accurate prediction. For example, some embodiments combine two ofthe processes, three of the processes, four of the processes, five ofthe processes, six of the processes, seven of the processes, or one ormore of the processes with another process not discussed.

In one embodiment, two or more of the above noted processes are combinedwith OR statements. For example, if Process 1 is true OR Process 2 istrue, then the probability of pathology is high. This combination hasthe benefit of allowing specialization of the processes to detectcertain types of pathologies and naturally increases the sensitivity ofthe detection system across multiple pathologies. In another embodiment,processes may be combined with AND statements. For example, if Process 1is true AND Process 2 is true, then the probability of pathology ishigh. This combination thus may create a highly specific detectionprocess. In another embodiment, processes may be combined as a linearcombination of continuous or categorical outputs. For example, if twoprocesses are combined, each which produce a continuous variable output,such as degrees C., the combined formulation may multiply each processvariable by a coefficient in order to obtain a final result which maythen be used to determine the probability of a pathology. In thisembodiment, the formulation may be in the form R=A*M1+B*M2 where R isrisk, M1 and M2 are Process 1 and Process 2 variables, and A and B arecoefficients. This combination technique has the added benefit ofweighting the variables unevenly, depending on which is more influentialon the pathology the researcher is interested in. Additionally it isoptimizable across all of the independent input variables simultaneouslyto obtain a system which maximizes sensitivity and/or specificitydepending on the aims of the researcher.

One skilled in the art will recognize that the optimization ofthresholds may be done on a per-process basis or for a set of processesin whatever combinations are used to optimize the sensitivity andspecificity of the combined set of processes.

Additionally, instead of applying simple thresholding (either for asingle set of foot temperature measurements at one time or for multiplesets of) to identify risk, the magnitude of any of the metrics given inthe discussed processes can also be informative of risk. For example, alarge difference in the temperature difference described in Process 1may indicate higher risk than a lower magnitude temperature difference.

Various embodiments of the invention may be implemented at least in partin any conventional computer programming language. For example, someembodiments may be implemented in a procedural programming language(e.g., “C”), or in an object oriented programming language (e.g.,“C++”). Other embodiments of the invention may be implemented aspreprogrammed hardware elements (e.g., application specific integratedcircuits, FPGAs, and digital signal processors), or other relatedcomponents.

In an alternative embodiment, the disclosed apparatus and methods (e.g.,see the various flow charts described above) may be implemented as acomputer program product (or in a computer process) for use with acomputer system. Such implementation may include a series of computerinstructions fixed either on a tangible medium, such as a computerreadable medium (e.g., a diskette, CD-ROM, ROM, or fixed disk) ortransmittable to a computer system, via a modem or other interfacedevice, such as a communications adapter connected to a network over amedium.

The medium may be either a tangible medium (e.g., optical or analogcommunications lines) or a medium implemented with wireless techniques(e.g., WIFI, microwave, infrared or other transmission techniques). Themedium also may be a non-transient medium. The series of computerinstructions can embody all or part of the functionality previouslydescribed herein with respect to the system. The processes describedherein are merely exemplary and it is understood that variousalternatives, mathematical equivalents, or derivations thereof fallwithin the scope of the present invention.

Those skilled in the art should appreciate that such computerinstructions can be written in a number of programming languages for usewith many computer architectures or operating systems. Furthermore, suchinstructions may be stored in any memory device, such as semiconductor,magnetic, optical or other memory devices, and may be transmitted usingany communications technology, such as optical, infrared, microwave, orother transmission technologies.

Among other ways, such a computer program product may be distributed asa removable medium with accompanying printed or electronic documentation(e.g., shrink wrapped software), preloaded with a computer system (e.g.,on system ROM or fixed disk), or distributed from a server or electronicbulletin board over the larger network (e.g., the Internet or World WideWeb). Of course, some embodiments of the invention may be implemented asa combination of both software (e.g., a computer program product) andhardware. Still other embodiments of the invention are implemented asentirely hardware, or entirely software.

The embodiments of the invention described above are intended to bemerely exemplary; numerous variations and modifications will be apparentto those skilled in the art. Such variations and modifications areintended to be within the scope of the present invention as defined byany of the appended claims.

What is claimed is:
 1. A method of detecting emergence of a foot ulceror a foot pre-ulcer, the method comprising: communicating the bottom ofa single foot with a modality comprising a body having a base with a topsurface having a receiving region configured to receive the bottom of asingle foot, the receiving region having a plurality of temperaturesensors in communication with the top surface of the receiving region,the plurality of temperature sensors being within the receiving region;activating the temperature sensors of the modality to ascertain acurrent temperature at each of a set of different locations of thebottom of the foot, the current temperatures being ascertained after thefoot is positioned in the receiving region of the base and in contactwith the top surface of the base, activating producing a set oftemperature values with each location having one associated temperaturevalue; producing a distribution of temperature values using the set oftemperature values, the distribution having an interpercentile rangebetween or including one or both the zero percentile and the one hundredpercentile of the set of temperature values wherein the interpercentilecomprises a temperature value difference between the temperatures at twodifferent percentiles; comparing the interpercentile range oftemperatures to a threshold value; and producing electronic outputinformation having information relating to the emergence of an ulcer orpre-ulcer when the interpercentile range size equals or exceeds thethreshold value.
 2. The method as defined by claim 13 wherein the set oftemperature values includes a maximum temperature value and a minimumtemperature value, the interpercentile range having the minimumtemperature value at the zero percentile and the maximum temperaturevalue at the one hundredth percentile.
 3. The method as defined by claim13 wherein the interpercentile range has a lowest temperature value thatis greater than the zero percentile and/or a highest temperature valuethat is less than the one hundredth percentile.
 4. The method as definedby claim 13 wherein the modality includes a thermal camera.
 5. Themethod as defined by claim 13 wherein the modality includes a closedplatform.
 6. The method as defined by claim 13 wherein the modalityincludes an open platform.
 7. The method as defined by claim 13 whereinthe threshold is between 1 degree C. and 4 degrees C.
 8. The method asdefined by claim 19 wherein the threshold is between 1.4 degrees C. and2.8 degrees C.
 9. The method as defined by claim 13 wherein the set ofdifferent locations comprises between four and six locations that relateto corresponding locations on the foot.
 10. The method as defined byclaim 13 wherein producing a distribution of temperature valuescomprises selecting a range between or including the zero percentile andthe one hundred percentile of the set of temperature values to be theinterpercentile range.
 11. The method as defined by claim 13 furthercomprising: determining ambient temperature of the environment;determining a central tendency statistic from the set of temperaturevalues, the central tendency statistic being one of mean, median, andmode of the set of temperature values; producing a given value as afunction of the central tendency statistic and the ambient temperature;and comparing the given value to a second threshold value, producingbeing a function of the comparison of the given value to the secondthreshold value.
 12. The method as defined by claim 23 wherein producinga given value comprises determining the difference between the centraltendency statistic and the ambient temperature.
 13. The method asdefined by claim 13 further comprising: comparing two of the set of thetemperature values to produce a comparison value; and determine thedifference between at least the comparison value and a third thresholdvalue, producing being a function of the difference between thecomparison value and the third threshold value.
 14. The method asdefined by claim 13 wherein the interpercentile range consists of atemperature value difference between the temperatures at two differentpercentiles.
 15. A method of detecting emergence of a foot ulcer or afoot pre-ulcer, the method comprising: communicating the bottom of asingle foot with a modality comprising a body having a base with a topsurface having a receiving region configured to receive the bottom of asingle foot, the receiving region having a plurality of temperaturesensors in communication with the top surface of the receiving region,the plurality of temperature sensors being within the receiving region;activating the temperature sensors of the modality to ascertain acurrent temperature at each of a set of different locations of thebottom of the foot, the current temperatures being ascertained after thefoot is positioned in the receiving region of the base and in contactwith the top surface of the base, activating producing a set oftemperature values with each location having one associated temperaturevalue; determining percentiles of the set of temperature values, thepercentiles forming an interpercentile range between or including one orboth the zero percentile and the one hundred percentile of the set oftemperature values wherein the interpercentile comprises a temperaturevalue difference between the temperatures at two different percentiles;comparing the interpercentile range of temperatures to a thresholdvalue; and producing electronic output information having informationrelating to the emergence of an ulcer or pre-ulcer as a function of itsrelationship to the interpercentile range.
 16. The method as defined byclaim 13 wherein the set of temperature values includes a maximumtemperature value and a minimum temperature value, the interpercentilerange having the minimum temperature value at the zero percentile andthe maximum temperature value at the one hundredth percentile.
 17. Themethod as defined by claim 13 wherein the interpercentile range has alowest temperature value that is greater than the zero percentile and/ora highest temperature value that is less than the one hundredthpercentile.
 18. The method as defined by claim 13 wherein the modalityincludes a thermal camera.
 19. The method as defined by claim 13 whereinsaid producing comprises producing electronic output information havinginformation relating to the emergence of an ulcer or pre-ulcer when theinterpercentile range size equals or exceeds the threshold value. 20.The method as defined by claim 13 wherein the interpercentile rangeconsists of a temperature value difference between the temperatures attwo different percentiles.
 21. The method as defined by claim 13 whereinthe modality comprises a closed platform.
 22. The method as defined byclaim 13 wherein the set of temperature values includes at least onecalculated temperature value between at least two temperature sensors.23. The method as defined by claim 13 further comprising producingelectronic information relating to foot ischemia as a function of itsrelationship to the interpercentile range.